What is spasm of the near reflex?
What is spasm of the near reflex?
Spasm of the near reflex (SNR) is when this triad persists when the patient is not fixating on a near object. Patients present with blurred vision, diplopia and asthenopia and on examination with often have an alternating convergent strabismus, abduction deficit and pseudomyopia.
What reflex is affected by near triad?
When changing our viewing from a distant to a near object, the near-reflex response comprising of ocular accommodation, convergence and pupil miosis is elicited to achieve and maintain clear and single binocular vision.
What is the near triad?
The near-vision triad, or complex, consists of convergence, miosis, and accommodation. Neuronal pathways that control each of these components are distinct but interrelated. Abnormalities affecting 1 or more components of the complex may present as eye pain, headache, blurred vision, or diplopia at near fixation.
What is convergence spasm?
Convergence spasm (CS) means intermittent episodes of convergence, miosis and accommodation with disconjugate gaze mimicking abducens palsy. The organic causes range from metabolic to host of neurological and ophthalmic diseases that we describe.
What causes spasm?
Muscle pain, fatigue, and overuse are the most common causes of muscle spasms. Other causes include stress or anxiety, which can lead to muscle twitches in the face. Trapped nerves can result in spasms in the back.
What is ciliary spasm?
A spasm of accommodation (also known as a ciliary spasm, an accommodation, or accommodative spasm) is a condition in which the ciliary muscle of the eye remains in a constant state of contraction. Normal accommodation allows the eye to “accommodate” for near-vision.
What does the blinking reflex involve?
The corneal blink reflex is caused by a loop between the trigeminal sensory nerves and the facial motor (VII) nerve innervation of the orbicularis oculi muscles. The reflex activates when a sensory stimulus contacts either free nerve endings or mechanoreceptors within the epithelium of the cornea.
What is the near reaction?
The accommodation reflex (or near response) is a three-part reflex that brings near objects into focus through lens thickening, pupillary constriction, and inward rotation of the eyes—eye convergence.
How do you detect near reflexes?
The near response pupil test measures the pupil’s response to a near target. 4 This test will be performed in a room with normal lighting. Your healthcare provider will ask you to look at a distant object, then move a small object or card in front of your eyes.
What causes convergence spasms?
There are several organic causes of convergence spasms, including encephalitis, tabes, labyrinthine fistulas, Arnold Chiari malformation, posterior fossa neurofibroma, trauma, and pituitary adenoma [3,4].